Rotary motor actuator and horizontal axis wind turbine

ABSTRACT

Provided is a rotary motor actuator capable of simplifying the manufacture and assembly process. 
     A base  22,  a table  21,  a stator  25  and a rotor  26  of a rotary motor  31  and a first member  12  and a second member  14  of a guide mechanism  24  have a plurality of base segments  22   a,  a plurality of table segments  21   a,  a plurality of stator segments  25   a,  a plurality of rotor segments  26   a,  a plurality of first member segments  12   a  and a plurality of second member segments  14,  respectively, which all arranged circumferentially around a center line C. The stator segments  25   a  are connected to the base segments  22   a,  to which the first member segments  12   a  are connected. The rotor segments  26   a  are connected to the table segments  21   a,  to which the second member segments  14   a  are connected.

TECHNICAL FIELD

The present invention relates to a rotary motor actuator that has atable rotating relative to a base around a predetermined center line,and to a horizontal axis wind turbine with the rotary motor actuatorbuilt therein.

BACKGROUND ART

A wind turbine is a device in which a rotor with aerofoils rotates bywind force thereby to convert wind energy to power of the rotor. Thehorizontal axis wind turbine is defined as a wind turbine in which therotation axis of the rotor is located approximately in the horizontalplane. On the ground, a tower is installed to support the rotor at apredetermined height above the ground. At the upper part of the tower, anacelle is arranged. In the nacelle, the rotation axis of the rotor, apower generator and a controller are accommodated. The power generatorgenerates power upon receiving the rotational force of the rotor.

Between the tower and the nacelle, there is installed a yaw drive unitfor turning the nacelle relative to the tower in the horizontal place inaccordance with the wind direction in such a manner that the aerofoilsare kept against the wind that varies in direction (for example, seePL1). A controller operates the yaw drive unit to control the deviationangle between the wind direction and the rotation axis of the rotor tobe a predetermined angle or less. The yaw drive unit has a largering-shaped gear provided in the tower and a geared motor with pinionprovided in the nacelle. The pinion of the geared motor engages with thering gear of the tower. When the geared motor is turned, the pinionrotates on its axis and rotates around the ring gear. With rotation ofthe pinion, the nacelle turns in the horizontal plane.

CITATION LIST Patent Literature

-   PL1: Japanese Patent Application Laid-Open No. 2007-107411

SUMMARY OF INVENTION Technical Problem

As the gears engage with each other, there exist backlash between thepinion and the gear. When the wind turbine is hit by blown wind or windin the lateral direction, the backlash causes the pinion and the gearinto friction, of which gear surfaces wear, sometimes resulting in earlybreakage.

If a direct drive system motor, which is capable of transmitting themotor rotation directly to the nacelle, is used, the transmission can beeliminated and the above-mentioned problem due to the backlash of thegears can be solved. However, a motor for maintaining the number ofrevolutions constantly low has a physical problem of upsizing in orderto obtain necessary torque as compared with the motor with a high numberof revolutions. When the motor is upsized, it is difficult tomanufacture, and as the weight increases with size, the assembly processof the motor at the upper part of the tower becomes dangerous.

Then, the present invention aims to provide a rotary motor actuatorcapable of simplifying the manufacturing and assembly process and alsoprovide a horizontal axis wind turbine with the rotary motor actuatorbuilt therein.

Solution to Problem

Hereinafter, explanation is made about the present invention.

In order to solve the above-mentioned problems, a first aspect of thepresent invention is a rotary motor actuator which has a table rotatingrelative to abase around a center line, comprising: a rotary motor thathas a stator and a rotor opposed to the stator and is configured torotate the table relative to the base around the center line; and aguide mechanism which has a first member and a second member mountedmovable on the first member via a plurality of rolling elements andwhich guides rotation of the table relative to the base around thecenter line, wherein the base, the table, the stator, the rotor, thefirst member and the second member have a plurality of base segments, aplurality of table segments, a plurality of stator segments, a pluralityof rotor segments, a plurality of first member segments and a pluralityof second member segments, respectively, which are arranged in acircumferential direction around the center line, one of the statorsegments and the rotor segments is connected to the base segments, andone of the first member segments and the second member segments isconnected to the base segments, and the other of the stator segments andthe rotor segments is connected to the table segments, and the other ofthe first member segments and the second member segments is connected tothe table segments.

Another aspect of the present invention is a horizontal axis windturbine having a yaw drive unit for turning a nacelle, which support arotor, relative to a tower around a yaw axis in such a manner that arotation axis of the rotor rotated by a wind force extends against wind,wherein the yaw drive unit has: a rotary motor that has a stator and arotor opposed to the stator and is configured to rotate a table fixed tothe nacelle relative to a base fixed to the tower around the yaw axis,and a guide mechanism which has a first member and a second membermounted movable on the first member via a plurality of rolling elementsand which guides rotation of the table relative to the base around theyaw axis, the base, the table, the stator, the rotor, the first memberand the second member have a plurality of base segments, a plurality oftable segments, a plurality of stator segments, a plurality of rotorsegments, a plurality of first member segments and a plurality of secondmember segments, respectively, which are arranged in a circumferentialdirection around the yaw axis, one of the stator segments and the rotorsegments is connected to the base segments, and one of the first membersegments and the second member segments is connected to the basesegments, and the other of the stator segments and the rotor segments isconnected to the table segments, and the other of the first membersegments and the second member segments is connected to the tablesegments.

Advantageous Effects of Invention

According to the rotary motor actuator of the one aspect of the presentinvention, the segments of the rotary motor and the segments of theguide mechanism are first combined into modules, which are thenassembled into the rotary motor actuator as a whole. With thisstructure, it is possible to facilitate the manufacture process of thelarge-sized rotary motor actuator.

According to the horizontal axis wind turbine of the other aspect of thepresent invention, the segments of the rotary motor and the segments ofthe guide mechanism are first combined into modules on the ground, whichare then arranged circumferentially around the yaw axis and assembled,in the air (at the upper part of the tower), into the yaw drive unit asa whole. With this structure, it is possible to simplify the assemblyprocess of the yaw drive unit in the air and also facilitate transfer ofthe modularized yaw drive unit to the air.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a horizontal axis wind turbine with arotary motor actuator according to one embodiment of the presentinvention built therein;

FIG. 2 is a plan view of a base side unit of the rotary motor actuator;

FIG. 3 is a cross sectional view of the rotary motor actuator (takenalong the line III-III of FIG. 2);

FIG. 4 is a plan view of a base side module;

FIG. 5 is across sectional view of the base side module (taken along theline V-V of FIG. 4);

FIG. 6 is a perspective view of the base side module;

FIG. 7 is a perspective view illustrating plural moving blocks 14arranged on a ring-shaped raceway rail; and

FIG. 8 is a horizontal cross sectional view of a moving block.

DESCRIPTION OF EMBODIMENTS

With reference to the attached drawings, description will be made abouta rotary motor actuator according to one embodiment of the presentinvention. FIG. 1 is a perspective view of a horizontal axis windturbine in which the rotary motor actuator according to the oneembodiment of the present invention is installed. This horizontal axiswind turbine is a device for rotating a rotor 4 with blades by windforce, and converting wind power energy into power for the rotor 4. Therotor 4 has a hub 2 that rotates around the horizontal rotation axis 3,a plurality of blades 1 arranged on the hub 2 radially, and a rotationaxis 3 that transmits rotation of the hub 2 to a transmission 5. The hub2 and plural blades 1 make up an aerofoil. The rotational force of therotation axis 3 of the rotor 4 is transmitted via the transmission 5 toa power generator 6. The power generator 6 generates power uponreceiving the rotational force of the rotor 4. The rotation axis 3 ofthe rotor 4, the transmission 5 and power generator 6 are accommodatedin a nacelle 7.

On the ground, a tower 8 is installed to support the rotor 4 at thepredetermined height. At the upper part of the tower 8, a nacelle 7 isarranged rotatable around the vertical axis. Between the tower 8 and thenacelle 7, a yaw drive unit 10 is arranged that turns the nacelle 7 inthe horizontal plane. The yaw drive unit 10 turns the nacelle 7 in thehorizontal plane in accordance with the wind direction in such a mannerthat the aerofoils of the rotor 4 are kept against the wind that variesin direction. A controller (not shown) stored in the nacelle 7 operatesthe yaw drive unit 10 to control a deviation angle between the winddirection and the rotation axis 3 of the rotor 4 to be a predeterminedangle or less. The rotary motor actuator according to the one embodimentof the present invention is arranged between the tower 8 and the nacelle7 to function as the yaw drive unit 10.

The horizontal axis wind turbine has a base side unit which is fixed tothe tower 8 and a table side unit which is fixed to the nacelle side.FIG. 2 is a plane view of the base side unit of the rotary motoractuator and FIG. 3 is a cross sectional view of the rotary motoractuator. Between the base 22 of the rotary motor actuator and the table21, the rotary motor 31 and the guide mechanism 24 are arranged. On thebase 22, a ring-shaped stator 25 of the rotary motor 31 is connectedthereto. On the table 21, a ring-shaped rotor 26 of the rotary motor 31is connected thereto.

Connected to the base 22 is a ring-shaped raceway rail 12 as the firstmember inside the ring-shaped stator 25. On the table 21, plural movingblocks 14 are connected as second members. The moving block 2 14 aremounted on the raceway rail 12 movable in the circumferential direction(see FIG. 7). The base side unit and the table side unit are equallysplit into, for example, five modules in this embodiment. In otherwords, the five modules are arranged circumferentially around the centerline C of rotation of the rotary motor 31.

FIG. 4 is a plan view of the base side module, FIG. 5 is a crosssectional view thereof and FIG. 6 is a perspective view thereof. Thebase side module has a base segment 22 a split into a sector, anarc-shaped stator segment 25 a connected to the upper surface of thebase segment 22 a, and an arc-shaped raceway rail segment 12 a connectedto the inside of the stator segment 25 a on the upper surface of thebase segment 22 a. That is, in the base side module, the stator segment25 a and the raceway rail segment 12 a are combined into one piece. Thebase segment 22 a is one obtained by splitting the ring-shaped stator 25into five. The raceway rail segment 12 a is one obtained by splittingthe ring-shaped raceway rail 12 into five. The base 22, the stator 25and the raceway rail 12 are equal in the number of split parts (five inthis embodiment), and the stator segments 25 a and the raceway railsegments 12 a are the respective base segments 22 a.

The base segment 22 a is formed into a sector shape. When five basesegments 22 a are combined, the ring-shaped base 22 is configured. Inthe outer rim of the base segment 22 a, through holes 33 are formed toconnect the base segment 22 to the upper part of the tower 8. The basesegment 22 is connected to the tower 8 by passing a bolt into eachthrough hole 33 and tightening the bolt to the upper part of the tower8.

On the upper surface of the base segment 22 a, the arc-shaped statorsegment 25 a is connected thereto. The stator segment 25 a is a core 16made of a magnetic material wound with plural coils 15. The core 16 hasan arc-shaped main body 16 a and a plurality of salient poles 16 bjutting from the main body 16 a radially to the inside (see FIG. 4).Each of salient poles 16 b is wound with the coils 15. The ring-shapedstator 25 is split equally and circumferentially and all the statorsegments 25 a are equal in circumferential length.

Every three coils 15 form one coil group of three-phase (U, V and Wphases) coils. When three-phase alternate current of which phase is120-degree shifted from each other flows into the three-phase coils 15,a moving magnetic field moving in the circumferential direction isgenerated on the salient poles 16 b of the core 16. The plural salientpoles 16 b of this core 16 faces rotor segment 26 a made of fieldpermanent magnet, which is described later, in such a manner as tocreate a magnetic gap therebetween. The stator segment 26 a is giventhrust by the moving magnetic field generated at the salient poles 16 bof the core 16 and turns around the center line C of the base 22 (seeFIG. 2). As illustrate d in FIG. 4, in the main body 16 a of the core16, through holes 35 are formed. The stator segment 25 a is connected tothe base segment 22 a by passing a bolt into each through hole 35 andtightening the volt to the base segment 22 a.

As illustrated in FIG. 6, the arc-shaped raceway rail segment 12 a isconnected to the inside of the stator segment 25 a on the upper surfaceof the base segment 22 a. In the inner peripheral surface of the racewayrail segment 12 a, two, upper and lower, rolling-element rolling grooves36 are formed along the circumferential direction for rolling balls asrolling elements. The number of rolling-element rolling grooves 36 maybe determined appropriately in accordance with load to bear. Eachrolling-element rolling groove 36 has a cross sectional shape ofcombined two arcs, that is Gothic arch groove. Balls 13 (see FIG. 3)interposed between the raceway rail segment 12 a and the moving block 14are in two-point contact with the Gothic arch groove. In the racewayrail segment 12 a, through holes 34 are formed. The raceway rail segment12 a is connected to the base segment 22 a by passing a bolt into eachthrough hole 34 an tightening the bolt to the base segment 22 a.

As illustrated in FIG. 3, the table 21 is split into five table segments21 a. The rotor 26 connected to the table 21 is also split into fiverotor segments 26 a. The table 21 and the rotor 26 are equal in thenumber of splits parts and each rotor segment 26 a is connected to acorresponding table segment 21 a.

The planar shape of the rotor segment 26 a connected to the bottomsurface of the table segment 21 a is an arc. The rotor segment 26 a isarranged radially outside the raceway rail segment 12 a and radiallyinside the stator segment 25 a. Between the rotor segment 26 a and thestator segment 25 a, there is created a magnetic gap g. In order toprevent interference between the raceway rail segment 12 a and the rotorsegment 26 a, a small gap is also created between the raceway rail 12 aand the rotor segment 26 a.

The rotor segment 26 a has a yoke 18 that is made of a magnetic materialand has a U-shaped cross section and permanent magnets 17 arranged inthe groove of the yoke 18. The yoke 18 extends in the circumferentialdirection and the plural permanent magnets 17 are arranged in the grooveof the yoke 18 in the circumferential direction. Each permanent magnet17 is magnetized radially. Plural permanent magnets are arranged in sucha manner that N poles and S poles are formed alternately in thecircumferential direction on the outer periphery of the rotor segment 26a. The rotor 26 is split circumferentially and equally and all the rotorsegments 26 are equal in circumferential length.

On the lower surface of the table segment 21 a, the moving block 14 isconnected thereto. FIG. 7 illustrates plural moving blocks 14 arrangedon the ring-formed raceway rail 12. On the inner peripheral surface ofthe raceway rail in the assembly state, plural, for example, five movingblocks 14 are arranged equally separated from each other in thecircumferential direction. The moving blocks 14 cooperate with theraceway rail 12 to guide the table 21 rotating relative to the base 22around the center line C. As the plural moving blocks 14 are arranged onthe raceway rail 12 equally separated from each other, it is possible toequally bear loads in 360-degree all directions on the table 21.

As described above, the table side module has a table segment 21 a, arotor segment 26 a connected to the lower surface of the table segment21 a and the moving block 14 connected to the lower surface of the tablesegment 21 a. That is, in the table side module, the rotor segment 26 aand the moving block 14 are combined into one piece.

Here, in this embodiment, five moving blocks 14 are connected to fivetable segments 21 a. However, there is no need to connect all the tablesegments 21 a to the moving blocks 14, and some table segments 21 a maybe not connected to the moving blocks 14 or one table segment 21 a maybe connected two or more moving blocks 14. The number of moving blocks14 may be two or more. If the number of table segments 21 a differs fromthe number of moving blocks 14, it is possible to avoid the possibilitythat all the moving blocks 14 are arranged at joints of the racewaysegments 12 a and thereby to smooth rotation of the table 21.

In the upper surface of the moving block 14, a plurality of tap holes 27is formed. As illustrated in FIG. 3, a bolt is passed through a throughhole 38 of the table segment 21 a and the bolt is fit in the tap hole 37of the moving block 14 thereby to connect the moving block 14 to thetable segment 21 a.

FIG. 8 is a horizontal cross sectional view of the moving block 14. Themoving block 14 is arranged in such a manner as to face the innerperipheral surface of the raceway rail segment 12 a and it is mounted onthe raceway rail segment 12 a via plural balls 13 rolling on therolling-element rolling groove 12 b of the raceway rail segment 12 a.Each moving block 14 has a block main body 40 and end plates 41 a fixedto both ends of the block main body 40. In the block main body 40, two,upper and lower, loaded rolling-element rolling grooves 40 a are formedopposed to the two, upper and lower, rolling-element rolling grooves 12b of the raceway rail segment 12 a. Each loaded rolling-element rollinggroove 40 a has across sectional shape composed of two arcs and it is aso-called Gothic arch groove. A loaded rolling-element rolling path isformed between the rolling-element rolling groove 12 b of the racewayrail segment 12 a and the loaded rolling-element rolling groove 40 a ofthe moving block 14. The balls 13 roll, under load, on this loadedrolling-element rolling path.

In the moving block main body 40, a rolling-element return path 40 b isformed approximately in parallel to the loaded rolling-element rollinggroove 40 a. In each end plate 41, a U-shaped direction change path 41 ais formed that connects the loaded rolling-element rolling groove 40 aof the moving block main body 40 to the rolling-element return path 40b. The rolling-element return path 40 b and the paired U-shapeddirection change paths 41 a form an unloaded return path that connectsone end of the loaded rolling-element rolling groove 40 a to the otherend. Once the paired endplates 41 are secured to the moving block mainbody 40, a circuitry rolling-element circulation path is completed.Here, in the assembled state, supporting means such as pressure ringsmay be arranged inside the moving block 14 in order to prevent themoving block 14 from being separated from the raceway rail 12.

As described above, after the base side modules are assembled one by one(in other words, the raceway rail segments 12 a and the stator segments25 a are connected to the respective base segments 22 a), the pluralbase segments 22 a are arranged in the circumferential direction aroundthe center line C and combined. Then, the arc-shaped stator segments 25a are connected together into a ring-shaped stator 25. Besides, thearc-shaped raceway rail segments 12 a are connected together into aring-shaped raceway rail 12.

In the same way, after the table side modules are assembled one by one(in other words, the rotor segments 26 a and the moving blocks 14 areconnected to the respective table segments 21 a), the plural tablesegments 21 a are arranged in the circumferential direction around thecenter line C and combined. Then, the arc-shaped rotor segments 26 a areconnected together into a ring-shaped rotor 26. When the moving blocks14 are mounted on the raceway rail 12, the rotary motor actuator iscompleted. When three-phase alternate current flows into coils 15 as thestator in this state, a rotational force is given to the table 21 sothat the table 21 rotates relative to the base 22.

When the above-described rotary motor actuator is mounted on thehorizontal axis wind turbine, first, the plural base side modules areassembled one by one on the ground and prepared as tower side modules.And, the plural table side modules are assembled one by one and preparedas nacelle side modules.

Next, at the upper part of the tower installed on the ground, the pluraltower side modules are arranged in the circumferential direction aroundthe yaw axis and combined integrally. With this process, the arc-shapedstator segments 25 a are connected together into the ring-shaped stator25. Besides, the arc-shaped raceway rail segments 12 a are connectedtogether into the ring-shaped raceway rail 12.

Then, at the upper part of the tower installed on the ground, the pluralnacelle side modules are arranged in the circumferential directionaround the yaw axis and combined together. With this process, thearc-shaped rotor segments 26 a are connected together into thering-shaped rotor 26. Then, the moving blocks 14 are mounted on theraceway rail 12, the guide mechanism is completed.

As described above, according to this embodiment, the rotary motoractuator can be manufactured by first combining and assembling thesegments of the rotary motor and segments of the guide mechanism intomodules and then, arranging the plural modules in the circumferentialdirection around the center line. This process makes it easy tomanufacture a large-sized rotary motor actuator.

As the curve guide having a curve raceway rail 12 and a plurality ofmoving blocks 14 mounted on the raceway rail 12 is used as the guidemechanism, it becomes easy to configure the guide mechanism comprised ofcircumferentially split parts.

As the base 22, the stator 25 and the raceway rail 12 are equal in thenumber of split parts and the stator segments 25 a and raceway segments12 a are connected to the respective base segments 22 a, manufacture ofeach module at the base side can be facilitated. Besides, as the table21 and the stator 26 are equal in the number of split parts and thetable segments 21 a are connected to the respective rotor segments 26 a,manufacture of each module at the table side can be facilitated.

As the rotary motor 31 is arranged radially outside the raceway rail 12,it is possible to increase the rotational force of the rotary motor 31.

As the raceway rail 12 is composed of plural arc-shaped raceway railsegments 12 a split therefrom, it is possible to improve the materialavailability and eliminate the need to use a large-sized processingmachine, as compared with the case of manufacturing an un-splitring-shaped raceway rail 12. This consequently facilitates themanufacturing process of the raceway rail itself.

When the rotary motor actuator of this embodiment is mounted in thehorizontal axis wind turbine, the rotary motor segments and the guidemechanism segments are combined into respective modules on the groundand then, the modules are arranged in the circumferential directionaround the yaw axis thereby to configure the yaw drive unit of thehorizontal axis wind turbine. With this configuration, it is possible tosimplify the assembly process of the yaw drive unit up in the air andalso the transfer process of the modularized yaw drive unit to the air.

Here, the present invention is not limited to the above-mentionedembodiments and may be embodied in various forms without departing fromthe scope of the present invention. In the above-described embodiments,the base is a fixed side and the table is a movable side. However, thesemaybe changed so that the table may be the fixed side and the base maybe the rotation side. Further, the base and the table may be usedflipped vertically.

Further, when it is used in a part which oscillates without making oneturn, it can use combined modules corresponding to required angles andthere is no need to combine all the modules into a ring.

Further, the guide mechanism used may be a slewing bearing that has anouter ring as a first member and an inner ring mounted on this outerring via rolling elements, other than the curve guide. The first membersegment may be an arc part as a part of the outer ring and the secondmember segment may be an arc part as a part of the inner ring.

Furthermore, the rotary motor may be arranged inside of the racewayrail. In this case, the rotary motor actuator may be more compact.

The present specification is based on Japanese Patent Applications No.2009-253251 filed on Nov. 4, 2009, the entire contents of which areexpressly incorporated by reference herein.

INDUSTRIAL APPLICABILITY

The rotary motor actuator of the present invention is applicable to theyaw drive unit for turning a rotation axis of a rotor of a horizontalaxis wind turbine in the horizontal plane as well as a pitch drive unitfor turning the rotation axis of the rotor in the vertical plane.Besides the wind turbine, it is applicable to a turning machine in whicha driver seat or an upper frame is mounted turnable relative to a trackframe as a lower structural element. It is also applicable to a turntable for turning a work such as a glass board for large-sized screendisplay.

REFERENCE NUMERALS

-   4 . . . rotor, 3 . . . rotation axis, 7 . . . nacelle, 8 . . .    tower, 10 . . . yaw drive unit, 12 . . . raceway rail (first    member), 12 a . . . raceway rail segment (first member segment), 14    . . . moving block (second member segment), 21 . . . table, 21 a . .    . table segment, 22 . . . base, 22 a . . . base segment, 24 . . .    guide mechanism, 25 . . . stator, 25 a . . . stator segment, 26 . .    . rotor, 26 a . . . rotor segment, 31 . . . rotary motor

1. A rotary motor actuator which has a table rotating relative to a basearound a center line, comprising: a rotary motor that has a stator and arotor opposed to the stator and is configured to rotate the tablerelative to the base around the center line; and a guide mechanism whichhas a first member and a second member mounted movable on the firstmember via a plurality of rolling elements and which guides rotation ofthe table relative to the base around the center line, wherein the base,the table, the stator, the rotor, the first member and the second memberhave a plurality of base segments, a plurality of table segments, aplurality of stator segments, a plurality of rotor segments, a pluralityof first member segments and a plurality of second member segments,respectively, which are arranged in a circumferential direction aroundthe center line, one of the stator segments and the rotor segments isconnected to the base segments, and one of the first member segments andthe second member segments is connected to the base segments, and theother of the stator segments and the rotor segments is connected to thetable segments, and the other of the first member segments and thesecond member segments is connected to the table segments.
 2. The rotarymotor actuator of claim 1, wherein the first member segments arearc-shaped raceway rail segments in which rolling-element rollinggrooves are formed in a longitudinal direction, and the second membersegments are moving blocks which have rolling-element circulation pathsincluding loaded rolling-element rolling grooves opposed to therolling-element rolling grooves of the raceway rail segments, therolling elements being arranged circulatably in the rolling-elementcirculation paths.
 3. The rotary motor actuator of claim 1, wherein thebase segments, the stator segments and the first member segments areequal in number, the stator segments and the first member segments areconnected to the base segments, respectively, the table segments and therotor segments are equal in number, and the rotor segments are connectedto the table segments, respectively.
 4. The rotary motor actuator ofclaim 1, wherein the rotary motor is arranged radially outside the guidemechanism.
 5. A method for manufacturing a rotary motor actuator having:a rotary motor that has a stator and a rotor opposed to the stator andis configured to rotate the table relative to the base around a centerline; and a guide mechanism which has a first member and a second membermounted movable on the first member via a plurality of rolling elementsand which guides rotation of the table relative to the base around thecenter line, the method comprising: a base side module forming step offorming a base side module by connecting one of a stator segment whichis a part of the stator and a rotor segment which is a part of the rotorto a base segment which is a part of the base and by connecting one of afirst member segment which is a part of the first member and a secondmember segment which is a part of the second member to the base segment;a table side module forming step of forming a table side module byconnecting the other of the stator segment and the rotor segment to atable segment which is a part of the table and by connecting the otherof the first member segment and the second member segment to the tablesegment; a base side unit forming step of arranging a plurality of baseside modules circumferentially around the center line to form one of thestator and the rotor and to form one of the first member and the secondmember; and a table side unit forming step of arranging a plurality oftable side modules circumferentially around the center line to form theother of the stator and the rotor and to form the other of the firstmember and the second member.
 6. A horizontal axis wind turbine having ayaw drive unit for turning a nacelle, which support a rotor, relative toa tower around a yaw axis in such a manner that a rotation axis of therotor rotated by a wind force extends against wind, wherein the yawdrive unit has: a rotary motor that has a stator and a rotor opposed tothe stator and is configured to rotate a table fixed to the nacellerelative to a base fixed to the tower around the yaw axis, and a guidemechanism which has a first member and a second member mounted movableon the first member via a plurality of rolling elements and which guidesrotation of the table relative to the base around the yaw axis, thebase, the table, the stator, the rotor, the first member and the secondmember have a plurality of base segments, a plurality of table segments,a plurality of stator segments, a plurality of rotor segments, aplurality of first member segments and a plurality of second membersegments, respectively, which are arranged in a circumferentialdirection around the yaw axis, one of the stator segments and the rotorsegments is connected to the base segments, and one of the first membersegments and the second member segments is connected to the basesegments, and the other of the stator segments and the rotor segments isconnected to the table segments, and the other of the first membersegments and the second member segments is connected to the tablesegments.
 7. A method for manufacturing a horizontal axis wind turbinehaving a yaw drive unit for turning a nacelle, which support a rotor,relative to a tower around a yaw axis in such a manner that a rotationaxis of the rotor rotated by a wind force extends against wind, whereinthe yaw drive unit has: a rotary motor that has a stator and a rotoropposed to the stator and is configured to rotate a table fixed to thenacelle relative to a base fixed to the tower around the yaw axis, and aguide mechanism which has a first member and a second member mountedmovable on the first member via a plurality of rolling elements andwhich guides rotation of the table relative to the base around the yawaxis, the method comprising: forming a plurality of base side moduleseach by connecting one of a stator segment which is a part of the statorand a rotor segment which is a part of the rotor to a base segment whichis a part of the base and by connecting one of a first member segmentwhich is a part of the first member and a second member segment which isa part of the second member to the base segment; forming a plurality oftable side modules each by connecting the other of the stator segmentand the rotor segment to a table segment which is a part of the tableand by connecting the other of the first member segment and the secondmember segment to the table segment; at an upper part of the towerinstalled on ground, arranging the base side modules circumferentiallyaround the yaw axis to form one of the stator and the rotor and to formone of the first member and the second member; and at the upper part ofthe tower installed on ground, arranging the table side modulescircumferentially around the yaw axis to form the other of the statorand the rotor and to form the other of the first member and the secondmember.
 8. The rotary motor actuator of claim 2, wherein the basesegments, the stator segments and the first member segments are equal innumber, the stator segments and the first member segments are connectedto the base segments, respectively, the table segments and the rotorsegments are equal in number, and the rotor segments are connected tothe table segments, respectively.
 9. The rotary motor actuator of claim2, wherein the rotary motor is arranged radially outside the guidemechanism.
 10. The rotary motor actuator of claim 3, wherein the rotarymotor is arranged radially outside the guide mechanism.